Cockroaches and clams have been far better at survival than humans so far.

Since I have your leave to disagree.

If you are talking about being better at survival, then the ability to survive a broader range of environments equals being a better survivor. Something humans do much better than roaches or clams. The ability to adapt your environment to suit your needs equals being the best survivor.

And correct, I know of no way to tell if a human is smarter than a cephalopod or elephant or dolphin.

Every living thing has some amount of intelligence. Some have more and some have less. Would you at least agree with that?

Oni writes:

For the sake of "drawing a line" lets call intelligence the ability to create art, music, do science, create mathematical equations and have complex communication.

Keeping this in mind, I am talking about where does this sort of intelligence come from. It comes down the evolutionary line and if it has evolved once in the universe then it has likely evolved more than once. In our case, intelligence has been selected billions of times in each tiny little step.

How can you possibly believe that we are not more intelligent than our evolutionary ancestors?

Keeping this in mind, I am talking about where does this sort of intelligence come from. It comes down the evolutionary line and if it has evolved once in the universe then it has likely evolved more than once. In our case, intelligence has been selected billions of times in each tiny little step.

How can you possibly believe that we are not more intelligent than our evolutionary ancestors?

Because "knowledge" and "intelligence" are not synonymous. I do not think that those things really are an indication of "intelligence" or even "human intelligence" but rather of technology, in particular the technology that humans created at a given time that allowed knowledge to be accumulated and passed on even beyond the personal contact circle.

But that still does not show that intelligence is a major evolutionary advantage.

The fact that something happened once does not mean that it is likely to happen again, only that it CAN happen again.

Human intelligence is not all that great in my opinion.

The invention of the concept of technology, of recording and passing on knowledge not just to close associates but to others has allowed a large accumulation of knowledge; but that is not a measure of intelligence. In addition, it is not the general human population that adds new knowledge but a very, very small segment of humans. And even there the majority of humans remain really ******** of the knowledge or tools, using only those advantages that do NOT require any of the characteristics Oni described or very much intelligence of any kind.

We have cash registers that calculate tax and how much change should be returned because the cashiers couldn't handle such tasks. We have politicians that try to limit how much and what knowledge can be taught. We have warnings on coffee lids that the coffee we just bought might be how, that we should not put our bodily orifices at the exhaust of Jet Skis, labels telling us not to stand above the top step of the ladder and back at that lid on my coffee, a suggestion to "drink here" at the hole in the lid.

Human intelligence evolved once in one line of the hominids, no other species has developed anything like our concept of technology or accumulating and dispersing knowledge.

That's over four billion year, about a third of the lifetime of the universe and out of millions if not billions of different species.

And if we look at the history of life on this earth, more intelligent species don't seem to have any particular advantage over less intelligent species. Other strategies seem to work equally well like high birth rates or having the biggest teeth or claws or being the biggest critter in the hood. Most everything in the sea eats the intelligent cuttle fish and octopus. Most everything in the jungle eats bonobos and chimpanzees. Elephants don't get eaten too often once they get to be the biggest critter out there. Few things attack crocks except the hippo that is even bigger and with bigger teeth.

There is no way I know of to accumulate intelligence.

If we ever do find other life it seems to me far more likely to be unintelligent. After all, most life here on earth has NO brain at all.

Anyone so limited that they can only spell a word one way is severely handicapped!

You said that you don't believe intelligence offers any evolutionary advantages (Message 62).

I responded that our intelligence seems to have been behind our unprecedented expansion across the globe, which indicates that it clearly is providing an exceptional evolutionary advantage (Message 67).

You responded by saying that the jury is still out, and nobody really knows whether intelligence is evolutionarily advantageous (Message 68).

I repeated my earlier rationale, which is that humans have expanded across the globe in a way that no other species ever has, and asserted that this is largely due to our intelligence, which provides clear evidence that intelligence has evolutionary advantages (Message 72).

You then told me that the advantages of intelligence weren't the point. You also said that it was technology, and not intelligence, that made humans so successful (Message 75).

I then argued that it wasn't the technology itself, but the ability to produce new technology on demand, that made humans successful; and identified that ability as intelligence (Message 82).

You repeated that the evolutionary-advantage thing wasn't the point, said something that demonstrated a complete misunderstanding of my point about intelligence and technology, and asked me something about comparing intelligent creatures and non-intelligent creatures (Message 85).

By this point, I was confused that you think your main discussion point on this thread is off-topic. I tried to explain that you can't determine whether something is evolutionarily advantageous---and therefore likely to evolve on other planets---simply by observing that it is less common than an alternative strategy, because the success of one strategy does not diminish the success of another (Message 88).

I said that I remember what the topic is, and that I was still commenting on it (Message 90).

You said that you didn't think my comments have anything to do with the topic, and decided that you would have to go slow so I can keep up (Message 91).

So, to summarize the summary: you said that intelligence isn't evolutionarily advantageous, so it likely won't be found on other planets. Then, I said it is advantageous and therefore is likely to be found on other planets, and pressed the issue a little. Then, you said it was off-topic, decided to talk about something else, and couldn't understand how my comments related to the topic.

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I don't know what else to tell you, Jar: I feel like I've kept up with the discussion very well and have focused very clearly on the topic, which is whether intelligent life is likely to be found on other planets. I have no idea why you think my comments have been off-topic or why you think my points are not convincing.

And, since other people have expressed similar confusion about your arguments, I'm relatively confident that I'm not the cause of the discussion problems we're having.

The bottom line is that intelligence is advantageous, because, in the one case we know it evolved, it played an integral role in an unprecedented expansion across the entire globe. Therefore, it seems reasonable to think it would be similarly successful on other planets.

Is there any species who's evolutionary history shows that they have become less intelligent over time?

Well, intelligence is a difficult thing to measure, so that's hard for us to say, but I'd say it's probable.

There's a lot of discussion about surviving, but evolutionary success is about a lot more than surviving. It's about leaving descendants. Sometimes the most effective strategy for doing so involves dying, so, not only is it easy to come up with a scenario a less intelligent creature could survive better (one in which instinctual response matters more than planning), it's too simplistic just to ask who will survive in some arbitrarily invented scenario as if that defines evolutionary success.

Intelligence doesn't necessarily lead you to make useful decisions for the propagation of your genes, and it's not free. Our brains consume a considerable amount of energy which requires us to consume more; the size of our heads makes birth difficult and dangerous; and the level of development our brains need leave us helpless as infants for much longer than most animals. These disadvantages to our big brains have obviously been outweighed by the advantages in our evolutionary history, but it's not clear that they always would be.

While it's difficult to declare a clear link between brain size and intelligence, there have been cases of species evolving smaller brains. The article I originally read on this subject was about bats, and about Homo floresiensis, but I can't find it now. Possibly, they just stumbled across a more efficient way of being just as intelligent with a smaller brain capacity. But I don't think we can dismiss the idea that, in certain environments, the greater energy efficiency of a smaller brain outweighed the advantages of being a bit cleverer.

You mentioned eyes later on, but they are also often reduced or lost in specific environments where the costs of eyes outweigh their advantages.

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On the subject of life elsewhere, there's one trait I can't see anyone mentioning yet, which I think would be likely to evolve given the existence of animals - heads.

Heads have evolved several times independently in different animal lineages, and it seems to make sense to have your major sensory equipment clustered close together with the bits you use to process sensory information. Once you've developed animals, I think heads aren't going to be too far behind.

However, I don't know if animals are at all likely. Prokaryotic life may well be common as muck, and many evolutionary changes we can expect to happen over a given period of time. But the development of the eukaryotic cell seems to be a very contingent, unusual event, which only happened once here on earth. Obviously, I've no idea how to calculate it's likeliness, and in the vast stretches of the cosmos maybe there's enough space for something similar to have happened over and over again. But it wouldn't surprise me if complex, multicellular life is exceedingly rare.

Yes, I know that but even if I didn't know that I could have figured it out.

Human intelligence evolved once in one line of the hominids, no other species has developed anything like our concept of technology or accumulating and dispersing knowledge.

There is no disputing that the level of intelligence in humans is unique on this planet. What is not unique is the process that led to that intelligence. Intelligence, to varying degrees, has evolved millions of times on this planet. Anything that has a brain has some degree of intelligence or cognitive ability. Anything that has a brain has the potential to evolve a more intelligent brain.

And if we look at the history of life on this earth, more intelligent species don't seem to have any particular advantage over less intelligent species. Other strategies seem to work equally well like high birth rates or having the biggest teeth or claws or being the biggest critter in the hood.

The success of less intelligent species is solely dependant on being suited to the existing environment. As Blue Jay points out it is about being successful in your niche. More intelligence means a bigger niche. It really is that simple.

There is no way I know of to accumulate intelligence.

It is called evolution. Now you know.

If we ever do find other life it seems to me far more likely to be unintelligent. After all, most life here on earth has NO brain at all.

I agree that 'unintelligent' life is probably much more abundant than intelligent life. I also think that, given enough time and environmental pressure, wherever you have life you will eventually have intelligent life.

The fact that something happened once does not mean that it is likely to happen again, only that it CAN happen again.

I am curious what the probability experts have to say about this. If the conditions in the universe are relatively homogenous, are the same processes not likely to repeat?

While it's difficult to declare a clear link between brain size and intelligence, there have been cases of species evolving smaller brains. The article I originally read on this subject was about bats, and about Homo floresiensis, but I can't find it now. Possibly, they just stumbled across a more efficient way of being just as intelligent with a smaller brain capacity. But I don't think we can dismiss the idea that, in certain environments, the greater energy efficiency of a smaller brain outweighed the advantages of being a bit cleverer.

What I remember is that it not so much size as it is surface area and interconnectivity. Male and female brains are different sizes on average but have the same degree of surface area and interconnectivity.

Increase in area and interconnectivity can also be seen in the degree of wrinkles in the outer layer. Apparently (iirc) one thing of note from Einsteins brain was a high level of interconnectivity between the two halves.

Is there any species who's evolutionary history shows that they have become less intelligent over time?

Well, intelligence is a difficult thing to measure, so that's hard for us to say, but I'd say it's probable.

I would agree -- evolution is a drunken walk that staggers back and forth -- in general.

But I also think there are thresholds, that intelligence alone is not sufficient to predict survival and reproductive success. Communication is such a threshold, with the ability to pass memes to following generations. Of course memes can be deleterious, neutral or beneficial, and they can change status in different ecologies ... but that they are a part of the hereditary lineage of a breeding population.

...not only is it easy to come up with a scenario a less intelligent creature could survive better (one in which instinctual response matters more than planning), it's too simplistic just to ask who will survive in some arbitrarily invented scenario as if that defines evolutionary success.

I agree and this is the key point. Intelligence allows it's possessor to survive a broader range of scenarios.

These disadvantages to our big brains have obviously been outweighed by the advantages in our evolutionary history, but it's not clear that they always would be.

I would say that the prevalence of brains in general would indicate that their cost is less than their benefit. I imagine that there is a point where the cost is greater than the benefit and in those cases I imagine that they wont last.

While it's difficult to declare a clear link between brain size and intelligence, there have been cases of species evolving smaller brains.

There may be a few cases where brain size has been reduced but for the most part, the brain size/body mass ratio has increased has it not?

We aren't the only animals that exhibit signs of intelligence. Indeed primates are not the only type of animal that exhibits signs of intelligence either.

Wiki on elephants writes:

Elephants are amongst the world's most intelligent species. With a mass of just over 5 kg (11 lb), elephant brains are larger than those of any other land animal, and although the largest whales have body masses twenty-fold those of a typical elephant, whale brains are barely twice the mass of an elephant's brain. The elephant's brain is similar to that of humans in terms of structure and complexity - such as the elephant's cortex having as many neurons as a human brain, suggesting convergent evolution.

That intelligence exists in a number of species does suggest that it provides evolutionary advantage at least in some contexts. That is why it evolved. This seems inarguable.

jar writes:

Most everything in the sea eats the intelligent cuttle fish and octopus. Most everything in the jungle eats bonobos and chimpanzees. Elephants don't get eaten too often once they get to be the biggest critter out there. Few things attack crocks except the hippo that is even bigger and with bigger teeth.

But man can, and does, hunt and eat all of these things. And we do it without being particularly strong, without having very impressive teeth or claws etc. We are able to do it because we as a species have taken the intelligence route and run with it to a degree greater than anything else on our planet.

That intelligence taken to a similar or greater degree on another planet somewhere would provide similar advantage seems pretty inarguable. Big teeth will get you so far. But communication and the intelligence to create technology that allows us to shape our environment and compete physically with critters that are far more physically impressive will trump teeth and claws.

Sorry but I still don't see how evolution can accumulate intelligence.

I'm not at all sure that the level of human intelligence is unique on this planet, but it is an outlier.

More intelligence does not always mean a bigger niche. Elephants do not have a bigger niche than antelopes.

Squid do not have a bigger niche than sharks.

Bonobos do not have a bigger niche than grasshoppers.

I agree that it is certainly possible that given enough time some level of intelligence might evolve, but human like technology is very, very, very unlikely and that technology is not solely a matter of intelligence as I have said many times before. An equal or even greater level of intelligence would not result in human like technology if the critter does not live on the surface of its planet, have a method of manipulating objects AND stumble upon and adopt our concept of technology and knowledge transfer.

Anyone so limited that they can only spell a word one way is severely handicapped!

But man can, and does, hunt and eat all of these things. And we do it without being particularly strong, without having very impressive teeth or claws etc. We are able to do it because we as a species have taken the intelligence route and run with it to a degree greater than anything else on our planet.

This raises another question: why haven't the other major predators taken the intelligence route instead of the tooth-and-claw route? Furthermore, most of the other notably intelligent animals seem to not be predators.

Could it be that the juxtaposition of technology and predation is the route to sapience?